JPH059448Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention relates to an improvement in the mounting structure of a ceramic valve for an internal combustion engine.

"Prior Art" Conventionally, an annular groove B is provided on the outer periphery of the stem of a valve A of an internal combustion engine, and a convex portion D provided on the inner wall of a cylinder C is engaged to hold the valve A together with a spring F via a spring retainer E. are doing. In addition, relatively lightweight metals and alloys are used as materials for Cottater C, but as engines have improved in performance in recent years, ceramics have been used in valves, which are particularly important in valve train systems, to increase output. , improving fuel efficiency and reducing noise.

``Problems to be solved by the invention'' However, in the above-mentioned conventional valve mounting structure, when metal is used for the valve, it is difficult to reduce weight or reduce noise to a certain extent in balance with the strength of the material against heat and impact. No reduction can be expected. Therefore, weight reduction and noise reduction can be achieved relatively easily by using ceramics, etc., but due to the unique properties of ceramics, such as stress concentration at the edges and weakness in tensile strength, for example, Valve surging, which tends to occur during rotation, causes breakage at the engagement portion between the valve support and the groove. Therefore, this invention aims to improve the above-mentioned drawbacks of the conventional ones, and uses ceramic valves to easily and reliably achieve weight reduction of the valve train system, while also trying to overcome the above-mentioned drawbacks peculiar to ceramics. It is something.

"Means for solving the problem" The first means is to provide an annular groove on the outer periphery of the stem of the ceramic valve, insert a ring in this annular groove, and support the annular groove provided on the inner periphery of the valve. This is a mounting structure for ceramic valves.

The second means is a mounting structure for the ceramic valve of the first means in which the ring is made of titanium or a titanium alloy.

The third means is that the annular groove provided on the inner periphery of the cylinder is open to the end of the ceramic valve shaft.
This is the mounting structure of the ceramic valve.

The fourth means is a mounting structure for the ceramic valve of the third means, in which the ring is made of titanium or a titanium alloy.

"Function" With the above structure, by attaching a ring to the annular groove provided on the outer circumference of the valve stem and the groove provided on the inner circumference of the valve that supports the valve, even if the valve is overloaded, the valve stem Since the force concentrated on the edge of the provided groove is dispersed by the ring, damage to the valve can be prevented.

In this case, if the ring is hollow, the ring absorbs and relieves the stress caused by overload through elastic deformation, making the damage prevention effect even more remarkable. It is preferable to use titanium or a titanium alloy as the material for the ring. Titanium alloy has a normal Young's modulus of 21000Kg/mm ²
It has a lower tensile strength of 11000Kg/mm ² compared to the average tensile strength of 50
Kg/ ^mm2 or more. A low Young's modulus means that the contact performance with respect to the groove provided in the stem is good, and it is possible to prevent partial contact or uneven contact. In addition, since the ring has sufficient strength, there is no concern about plastic deformation of the ring due to insufficient strength. Furthermore, if the ring is made of a shape memory alloy, the inner diameter of the ring is deformed to a greater extent than the outer diameter of the annular groove of the stem, and the inner diameter is shortened at the position of the annular groove using the shape memory effect. The shape is endless, which alleviates stress concentration on the ceramic corresponding to the cut.

Furthermore, if the annular groove provided on the inner periphery of the cylinder is open toward the end of the ceramic valve shaft, assembly becomes easier. In other words, all you have to do is hold the valve spring with a spring retainer, attach the retainer, and then fit the rings into their respective annular grooves.

"Example" This invention will be further explained with reference to an example shown in the drawings.

1 is a valve made of ceramic; 2 is a valve spring; the valve 1 is supported by a spring retainer 3 and a spring retainer 4;
It is moved up and down by the operation of the rocker arm 10. FIG. 2 shows an embodiment of this invention. First, an annular groove 7 is provided on the outer periphery of the stem of the valve 1, and an annular groove 6 is also provided at a corresponding position on the end face of the valve 4. The ring 5 is installed between the annular grooves 6 and 7 so as to be in contact with both, and even if stress is concentrated on the edge of the annular groove 6 of the stem of the valve 1 made of ceramic, the ring 5 deforms appropriately. and ring groove 7 of valve 1.
Since excessive stress is not applied to this part, damage to this part can be prevented. In the above structure, the cylinder 4 is made of SCM435, the ring 5 is made of 99% Ti, the valve 1 is made of 94% silicon nitride sintered body, and the single cylinder 50 c.c.
We applied this to an engine and ran 20,000 cycles of idle racing at 12,000 rpm, but no abnormality was found in valve 1. FIG. 3 shows the ring 5 made hollow, which connects the annular groove 7 of the stem of the ceramic valve 1 and the annular groove 6 provided in the heater 4 via the hollow ring 8. By making the hollow ring 8 more easily deformable, it is possible to achieve improved durability when receiving an impact from the valve 1.Furthermore, by making the hollow ring 8 from a shape memory alloy, it is possible to achieve high durability. Even if an overload is applied to the valve during rotation or high temperature, the ring 8 is only deformed, and when the overload disappears and the steady state is reached, the superelastic effect of the shape memory alloy allows the valve to return to its original state. It is tightly supported by a spring retainer. Reference numeral 9 denotes a cut portion appropriately provided in the ring 5 to facilitate installation into the grooves 6 and 7.

(Effect of the invention) As described above, by providing grooves in both the valve stem and the valve stem, and interposing a solid or hollow ring between them, stress is applied to the edge of the groove provided in the stem of the ceramic valve. Even if it is concentrated, it can be dispersed to prevent damage to the valve.
It has an excellent effect of improving fuel efficiency and noise reduction.

[Brief explanation of the drawing]

Figure 1 shows the valve of this invention installed, Figures 2 and 3 show a side view of an embodiment of this invention, Figure 4 shows a ring, and Figure 5 shows a side view of a conventional example. be. 1...Ceramic valve, 2...Valve spring, 3...Spring retainer, 4...Cotter, 5...Ring, 6, 7...Ring groove, 8...Hollow ring.

Claims (1)

[Claims for Utility Model Registration] (1) Installation of a ceramic valve in which an annular groove is provided on the outer periphery of the stem of the ceramic valve, a ring is inserted into the annular groove, and the ring supports an annular groove provided on the inner periphery of the heater. structure. (2) The mounting structure for a ceramic valve as set forth in claim 1 of the utility model registration claim, in which the ring is made of titanium or a titanium alloy. (3) The mounting structure for a ceramic valve according to claim 1, wherein the annular groove provided on the inner periphery of the heater is open toward the end of the ceramic valve shaft. (4) The mounting structure for a ceramic valve as set forth in claim 3 of the utility model registration, in which the ring is made of titanium or a titanium alloy.